Populations of ceramic particles may be used in a wide variety of industrial processes and products including, for example: abrasive media; as a granular coating for asphalt based roofing shingle; as filtration medium for liquids; as a substitute for sand in investment casting processes; and as proppants in a down hole drilling operations where the ceramic particles may be referred to as proppants. Proppants made from ceramic particles may be used in deep wells where the pressure exerted on the ceramic proppant exceeds the crush resistance of conventional proppants such as sand and resin coated sand.
Examples of patents and published patent applications directed to proppants include: U.S. Pat. No. 3,376,930; U.S. Pat. No. 4,632,876; U.S. Pat. No. 7,067,445; U.S. Pat. No. 7,528,096; US 2006/0177661 and US 2008/0000638.